12 Search Results for "Yamada, Akihisa"

Document
DOI: 10.4230/LIPIcs.ITP.2025.23
Formalizing the Hidden Number Problem in Isabelle/HOL

Authors: Sage Binder, Eric Ren, and Katherine Kosaian

Published in: LIPIcs, Volume 352, 16th International Conference on Interactive Theorem Proving (ITP 2025)

Abstract
We formalize the hidden number problem (HNP), as introduced in a seminal work by Boneh and Venkatesan in 1996, in Isabelle/HOL. Intuitively, the HNP involves demonstrating the existence of an algorithm (the "adversary") which can compute (with high probability) a hidden number α given access to a bit-leaking oracle. Originally developed to establish the security of Diffie-Hellman key exchange, the HNP has since been used not only for protocol security but also in cryptographic attacks, including notable ones on DSA and ECDSA. Further, as the HNP establishes an expressive paradigm for reasoning about security in the context of information leakage, many HNP variants for other specialized cryptographic applications have since been developed. A main contribution of our work is explicating and clarifying the HNP proof blueprint from the original source material; naturally, formalization forces us to make all assumptions and proof steps precise and transparent. For example, the source material did not explicitly define the adversary and only abstractly defined what information is being leaked; our formalization concretizes both definitions. Additionally, the HNP makes use of an instance of Babai’s nearest plane algorithm, which solves the approximate closest vector problem; we formalize this as a result of independent interest. Our formalizations of Babai’s algorithm and the HNP adversary are executable, setting up potential future work, e.g. in developing formally verified instances of cryptographic attacks.
Cite as

Sage Binder, Eric Ren, and Katherine Kosaian. Formalizing the Hidden Number Problem in Isabelle/HOL. In 16th International Conference on Interactive Theorem Proving (ITP 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 352, pp. 23:1-23:19, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{binder_et_al:LIPIcs.ITP.2025.23,
  author =	{Binder, Sage and Ren, Eric and Kosaian, Katherine},
  title =	{{Formalizing the Hidden Number Problem in Isabelle/HOL}},
  booktitle =	{16th International Conference on Interactive Theorem Proving (ITP 2025)},
  pages =	{23:1--23:19},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-396-6},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{352},
  editor =	{Forster, Yannick and Keller, Chantal},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ITP.2025.23},
  URN =		{urn:nbn:de:0030-drops-246216},
  doi =		{10.4230/LIPIcs.ITP.2025.23},
  annote =	{Keywords: hidden number problem, Babai’s nearest plane algorithm, cryptography, interactive theorem proving, Isabelle/HOL}
}
Document
DOI: 10.4230/LIPIcs.ITP.2025.10
An Isabelle/HOL Formalization of Semi-Thue and Conditional Semi-Thue Systems

Authors: Dohan Kim

Published in: LIPIcs, Volume 352, 16th International Conference on Interactive Theorem Proving (ITP 2025)

Abstract
We present a formalized framework for semi-Thue and conditional semi-Thue systems for studying monoids and their word problem using the Isabelle/HOL proof assistant. We provide a formalized decision procedure for the word problem of monoids if they are finitely presented by complete semi-Thue systems. In particular, we present a new formalized method for checking confluence using (conditional) critical pairs for certain conditional semi-Thue systems. We propose and formalize an inference system for generating conditional equational theories and Thue congruences using conditional semi-Thue systems. Then we provide a new formalized decision procedure for the word problem of monoids which have finite complete (reductive) conditional presentations.
Cite as

Dohan Kim. An Isabelle/HOL Formalization of Semi-Thue and Conditional Semi-Thue Systems. In 16th International Conference on Interactive Theorem Proving (ITP 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 352, pp. 10:1-10:20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{kim:LIPIcs.ITP.2025.10,
  author =	{Kim, Dohan},
  title =	{{An Isabelle/HOL Formalization of Semi-Thue and Conditional Semi-Thue Systems}},
  booktitle =	{16th International Conference on Interactive Theorem Proving (ITP 2025)},
  pages =	{10:1--10:20},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-396-6},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{352},
  editor =	{Forster, Yannick and Keller, Chantal},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ITP.2025.10},
  URN =		{urn:nbn:de:0030-drops-246081},
  doi =		{10.4230/LIPIcs.ITP.2025.10},
  annote =	{Keywords: semi-Thue systems, conditional semi-Thue systems, conditional string rewriting, monoids, word problem}
}
Document
DOI: 10.4230/LIPIcs.MFCS.2025.76
Deciding Termination of Simple Randomized Loops

Authors: Éléanore Meyer and Jürgen Giesl

Published in: LIPIcs, Volume 345, 50th International Symposium on Mathematical Foundations of Computer Science (MFCS 2025)

Abstract
We show that universal positive almost sure termination (UPAST) is decidable for a class of simple randomized programs, i.e., it is decidable whether the expected runtime of such a program is finite for all inputs. Our class contains all programs that consist of a single loop, with a linear loop guard and a loop body composed of two linear commuting and diagonalizable updates. In each iteration of the loop, the update to be carried out is picked at random, according to a fixed probability. We show the decidability of UPAST for this class of programs, where the program’s variables and inputs may range over various sub-semirings of the real numbers. In this way, we extend a line of research initiated by Tiwari in 2004 into the realm of randomized programs.
Cite as

Éléanore Meyer and Jürgen Giesl. Deciding Termination of Simple Randomized Loops. In 50th International Symposium on Mathematical Foundations of Computer Science (MFCS 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 345, pp. 76:1-76:19, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{meyer_et_al:LIPIcs.MFCS.2025.76,
  author =	{Meyer, \'{E}l\'{e}anore and Giesl, J\"{u}rgen},
  title =	{{Deciding Termination of Simple Randomized Loops}},
  booktitle =	{50th International Symposium on Mathematical Foundations of Computer Science (MFCS 2025)},
  pages =	{76:1--76:19},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-388-1},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{345},
  editor =	{Gawrychowski, Pawe{\l} and Mazowiecki, Filip and Skrzypczak, Micha{\l}},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.MFCS.2025.76},
  URN =		{urn:nbn:de:0030-drops-241833},
  doi =		{10.4230/LIPIcs.MFCS.2025.76},
  annote =	{Keywords: decision procedures, randomized programs, linear loops, positive almost sure termination}
}
Document
DOI: 10.4230/LIPIcs.FSCD.2025.6
Weighted Rewriting: Semiring Semantics for Abstract Reduction Systems

Authors: Emma Ahrens, Jan-Christoph Kassing, Jürgen Giesl, and Joost-Pieter Katoen

Published in: LIPIcs, Volume 337, 10th International Conference on Formal Structures for Computation and Deduction (FSCD 2025)

Abstract
We present novel semiring semantics for abstract reduction systems (ARSs). More precisely, we provide a weighted version of ARSs, where the reduction steps induce weights from a semiring. Inspired by provenance analysis in database theory and logic, we obtain a formalism that can be used for provenance analysis of arbitrary ARSs. Our semantics handle (possibly unbounded) non-determinism and possibly infinite reductions. Moreover, we develop several techniques to prove upper and lower bounds on the weights resulting from our semantics, and show that in this way one obtains a uniform approach to analyze several different properties like termination, derivational complexity, space complexity, safety, as well as combinations of these properties.
Cite as

Emma Ahrens, Jan-Christoph Kassing, Jürgen Giesl, and Joost-Pieter Katoen. Weighted Rewriting: Semiring Semantics for Abstract Reduction Systems. In 10th International Conference on Formal Structures for Computation and Deduction (FSCD 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 337, pp. 6:1-6:21, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{ahrens_et_al:LIPIcs.FSCD.2025.6,
  author =	{Ahrens, Emma and Kassing, Jan-Christoph and Giesl, J\"{u}rgen and Katoen, Joost-Pieter},
  title =	{{Weighted Rewriting: Semiring Semantics for Abstract Reduction Systems}},
  booktitle =	{10th International Conference on Formal Structures for Computation and Deduction (FSCD 2025)},
  pages =	{6:1--6:21},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-374-4},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{337},
  editor =	{Fern\'{a}ndez, Maribel},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSCD.2025.6},
  URN =		{urn:nbn:de:0030-drops-236215},
  doi =		{10.4230/LIPIcs.FSCD.2025.6},
  annote =	{Keywords: Rewriting, Semirings, Semantics, Termination, Verification}
}
Document
DOI: 10.4230/LIPIcs.CSL.2025.47
A Rewriting Theory for Quantum λ-Calculus

Authors: Claudia Faggian, Gaetan Lopez, and Benoît Valiron

Published in: LIPIcs, Volume 326, 33rd EACSL Annual Conference on Computer Science Logic (CSL 2025)

Abstract
Quantum lambda calculus has been studied mainly as an idealized programming language - the evaluation essentially corresponds to a deterministic abstract machine. Very little work has been done to develop a rewriting theory for quantum lambda calculus. Recent advances in the theory of probabilistic rewriting give us a way to tackle this task with tools unavailable a decade ago. Our primary focus are standardization and normalization results.
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Claudia Faggian, Gaetan Lopez, and Benoît Valiron. A Rewriting Theory for Quantum λ-Calculus. In 33rd EACSL Annual Conference on Computer Science Logic (CSL 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 326, pp. 47:1-47:22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{faggian_et_al:LIPIcs.CSL.2025.47,
  author =	{Faggian, Claudia and Lopez, Gaetan and Valiron, Beno\^{i}t},
  title =	{{A Rewriting Theory for Quantum \lambda-Calculus}},
  booktitle =	{33rd EACSL Annual Conference on Computer Science Logic (CSL 2025)},
  pages =	{47:1--47:22},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-362-1},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{326},
  editor =	{Endrullis, J\"{o}rg and Schmitz, Sylvain},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CSL.2025.47},
  URN =		{urn:nbn:de:0030-drops-228046},
  doi =		{10.4230/LIPIcs.CSL.2025.47},
  annote =	{Keywords: quantum lambda-calculus, probabilistic rewriting, operational semantics, asymptotic normalization, principles of quantum programming languages}
}
Document
DOI: 10.4230/LIPIcs.CSL.2025.31
Simple Types for Probabilistic Termination

Authors: Willem Heijltjes and Georgina Majury

Published in: LIPIcs, Volume 326, 33rd EACSL Annual Conference on Computer Science Logic (CSL 2025)

Abstract
We present a new typing discipline to guarantee the probability of termination in probabilistic lambda-calculi. The main contribution is a particular naturality and simplicity: our probabilistic types are as simple types, but generated from probabilities as base types, representing a least probability of termination. Simple types are recovered by restricting probabilities to one. Our vehicle is the Probabilistic Event Lambda-Calculus by Dal Lago, Guerrieri, and Heijltjes, which presents a solution to the issue of confluence in probabilistic lambda-calculi. Our probabilistic type system provides an alternative solution to that using counting quantifiers by Antonelli, Dal Lago, and Pistone, for the same calculus. The problem that both type systems address is to give a lower bound on the probability that terms head-normalize. Following the recent Functional Machine Calculus by Heijltjes, our development takes the (simplified) Krivine machine as primary, and proceeds via an extension of the calculus with sequential composition and identity on the machine. Our type system then gives a natural account of termination probability on the Krivine machine, reflected back onto head-normalization for the original calculus. In this way we are able to avoid the use of counting quantifiers, while improving on the termination bounds given by Antonelli, Dal Lago, and Pistone.
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Willem Heijltjes and Georgina Majury. Simple Types for Probabilistic Termination. In 33rd EACSL Annual Conference on Computer Science Logic (CSL 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 326, pp. 31:1-31:21, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

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@InProceedings{heijltjes_et_al:LIPIcs.CSL.2025.31,
  author =	{Heijltjes, Willem and Majury, Georgina},
  title =	{{Simple Types for Probabilistic Termination}},
  booktitle =	{33rd EACSL Annual Conference on Computer Science Logic (CSL 2025)},
  pages =	{31:1--31:21},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-362-1},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{326},
  editor =	{Endrullis, J\"{o}rg and Schmitz, Sylvain},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CSL.2025.31},
  URN =		{urn:nbn:de:0030-drops-227885},
  doi =		{10.4230/LIPIcs.CSL.2025.31},
  annote =	{Keywords: lambda-calculus, probabilistic termination, simple types}
}
Document
DOI: 10.4230/LIPIcs.FSCD.2024.27
A Verified Algorithm for Deciding Pattern Completeness

Authors: René Thiemann and Akihisa Yamada

Published in: LIPIcs, Volume 299, 9th International Conference on Formal Structures for Computation and Deduction (FSCD 2024)

Abstract
Pattern completeness is the property that the left-hand sides of a functional program cover all cases w.r.t. pattern matching. In the context of term rewriting a related notion is quasi-reducibility, a prerequisite if one wants to perform ground confluence proofs by rewriting induction. In order to certify such confluence proofs, we develop a novel algorithm that decides pattern completeness and that can be used to ensure quasi-reducibility. One of the advantages of the proposed algorithm is its simple structure: it is similar to that of a regular matching algorithm and, unlike an existing decision procedure for quasi-reducibility, it avoids enumerating all terms up to a given depth. Despite the simple structure, proving the correctness of the algorithm is not immediate. Therefore we formalize the algorithm and verify its correctness using the proof assistant Isabelle/HOL. To this end, we not only verify some auxiliary algorithms, but also design an Isabelle library on sorted term rewriting. Moreover, we export the verified code in Haskell and experimentally evaluate its performance. We observe that our algorithm significantly outperforms existing algorithms, even including the pattern completeness check of the GHC Haskell compiler.
Cite as

René Thiemann and Akihisa Yamada. A Verified Algorithm for Deciding Pattern Completeness. In 9th International Conference on Formal Structures for Computation and Deduction (FSCD 2024). Leibniz International Proceedings in Informatics (LIPIcs), Volume 299, pp. 27:1-27:17, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

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@InProceedings{thiemann_et_al:LIPIcs.FSCD.2024.27,
  author =	{Thiemann, Ren\'{e} and Yamada, Akihisa},
  title =	{{A Verified Algorithm for Deciding Pattern Completeness}},
  booktitle =	{9th International Conference on Formal Structures for Computation and Deduction (FSCD 2024)},
  pages =	{27:1--27:17},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-323-2},
  ISSN =	{1868-8969},
  year =	{2024},
  volume =	{299},
  editor =	{Rehof, Jakob},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSCD.2024.27},
  URN =		{urn:nbn:de:0030-drops-203566},
  doi =		{10.4230/LIPIcs.FSCD.2024.27},
  annote =	{Keywords: Isabelle/HOL, pattern matching, term rewriting}
}
Document
DOI: 10.4230/LIPIcs.ITP.2023.34
Formalizing Results on Directed Sets in Isabelle/HOL (Proof Pearl)

Authors: Akihisa Yamada and Jérémy Dubut

Published in: LIPIcs, Volume 268, 14th International Conference on Interactive Theorem Proving (ITP 2023)

Abstract
Directed sets are of fundamental interest in domain theory and topology. In this paper, we formalize some results on directed sets in Isabelle/HOL, most notably: under the axiom of choice, a poset has a supremum for every directed set if and only if it does so for every chain; and a function between such posets preserves suprema of directed sets if and only if it preserves suprema of chains. The known pen-and-paper proofs of these results crucially use uncountable transfinite sequences, which are not directly implementable in Isabelle/HOL. We show how to emulate such proofs by utilizing Isabelle/HOL’s ordinal and cardinal library. Thanks to the formalization, we relax some conditions for the above results.
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Akihisa Yamada and Jérémy Dubut. Formalizing Results on Directed Sets in Isabelle/HOL (Proof Pearl). In 14th International Conference on Interactive Theorem Proving (ITP 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 268, pp. 34:1-34:13, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)

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@InProceedings{yamada_et_al:LIPIcs.ITP.2023.34,
  author =	{Yamada, Akihisa and Dubut, J\'{e}r\'{e}my},
  title =	{{Formalizing Results on Directed Sets in Isabelle/HOL (Proof Pearl)}},
  booktitle =	{14th International Conference on Interactive Theorem Proving (ITP 2023)},
  pages =	{34:1--34:13},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-284-6},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{268},
  editor =	{Naumowicz, Adam and Thiemann, Ren\'{e}},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ITP.2023.34},
  URN =		{urn:nbn:de:0030-drops-184092},
  doi =		{10.4230/LIPIcs.ITP.2023.34},
  annote =	{Keywords: Directed Sets, Completeness, Scott Continuous Functions, Ordinals, Isabelle/HOL}
}
Document
Invited Talk
DOI: 10.4230/LIPIcs.FSCD.2023.4
Termination of Term Rewriting: Foundation, Formalization, Implementation, and Competition (Invited Talk)

Authors: Akihisa Yamada

Published in: LIPIcs, Volume 260, 8th International Conference on Formal Structures for Computation and Deduction (FSCD 2023)

Abstract
Automated termination analysis is a central topic in the research of term rewriting. In this talk, I will first review the theoretical foundation of termination of term rewriting, leading to the recently established tuple interpretation method. Then I will present an Isabelle/HOL formalization of the theory. Although the formalization is based on the existing library IsaFoR (Isabelle Formalization of Rewriting), the present work takes another approach of representing relations (predicates rather than sets) so that the notation is more human friendly. Then I will present a unified implementation of the termination analysis techniques via SMT encoding, leading to the termination prover NaTT. Many tools have been developed for termination analysis and have been competing annually in termCOMP (Termination Competition) for two decades. At the end of the talk, I will share my experience in organizing termCOMP in the last five years.
Cite as

Akihisa Yamada. Termination of Term Rewriting: Foundation, Formalization, Implementation, and Competition (Invited Talk). In 8th International Conference on Formal Structures for Computation and Deduction (FSCD 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 260, pp. 4:1-4:5, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)

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@InProceedings{yamada:LIPIcs.FSCD.2023.4,
  author =	{Yamada, Akihisa},
  title =	{{Termination of Term Rewriting: Foundation, Formalization, Implementation, and Competition}},
  booktitle =	{8th International Conference on Formal Structures for Computation and Deduction (FSCD 2023)},
  pages =	{4:1--4:5},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-277-8},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{260},
  editor =	{Gaboardi, Marco and van Raamsdonk, Femke},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSCD.2023.4},
  URN =		{urn:nbn:de:0030-drops-179882},
  doi =		{10.4230/LIPIcs.FSCD.2023.4},
  annote =	{Keywords: Term rewriting, Termination, Isabelle/HOL, Competition}
}
Document
Invited Talk
DOI: 10.4230/LIPIcs.FSCD.2020.4
Certifying the Weighted Path Order (Invited Talk)

Authors: René Thiemann, Jonas Schöpf, Christian Sternagel, and Akihisa Yamada

Published in: LIPIcs, Volume 167, 5th International Conference on Formal Structures for Computation and Deduction (FSCD 2020)

Abstract
The weighted path order (WPO) unifies and extends several termination proving techniques that are known in term rewriting. Consequently, the first tool implementing WPO could prove termination of rewrite systems for which all previous tools failed. However, we should not blindly trust such results, since there might be problems with the implementation or the paper proof of WPO. In this work, we increase the reliability of these automatically generated proofs. To this end, we first formally prove the properties of WPO in Isabelle/HOL, and then develop a verified algorithm to certify termination proofs that are generated by tools using WPO. We also include support for max-polynomial interpretations, an important ingredient in WPO. Here we establish a connection to an existing verified SMT solver. Moreover, we extend the termination tools NaTT and TTT2, so that they can now generate certifiable WPO proofs.
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René Thiemann, Jonas Schöpf, Christian Sternagel, and Akihisa Yamada. Certifying the Weighted Path Order (Invited Talk). In 5th International Conference on Formal Structures for Computation and Deduction (FSCD 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 167, pp. 4:1-4:20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)

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@InProceedings{thiemann_et_al:LIPIcs.FSCD.2020.4,
  author =	{Thiemann, Ren\'{e} and Sch\"{o}pf, Jonas and Sternagel, Christian and Yamada, Akihisa},
  title =	{{Certifying the Weighted Path Order}},
  booktitle =	{5th International Conference on Formal Structures for Computation and Deduction (FSCD 2020)},
  pages =	{4:1--4:20},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-155-9},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{167},
  editor =	{Ariola, Zena M.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSCD.2020.4},
  URN =		{urn:nbn:de:0030-drops-123263},
  doi =		{10.4230/LIPIcs.FSCD.2020.4},
  annote =	{Keywords: certification, Isabelle/HOL, reduction order, termination analysis}
}
Document
DOI: 10.4230/LIPIcs.ITP.2019.30
Complete Non-Orders and Fixed Points

Authors: Akihisa Yamada and Jérémy Dubut

Published in: LIPIcs, Volume 141, 10th International Conference on Interactive Theorem Proving (ITP 2019)

Abstract
In this paper, we develop an Isabelle/HOL library of order-theoretic concepts, such as various completeness conditions and fixed-point theorems. We keep our formalization as general as possible: we reprove several well-known results about complete orders, often without any property of ordering, thus complete non-orders. In particular, we generalize the Knaster - Tarski theorem so that we ensure the existence of a quasi-fixed point of monotone maps over complete non-orders, and show that the set of quasi-fixed points is complete under a mild condition - attractivity - which is implied by either antisymmetry or transitivity. This result generalizes and strengthens a result by Stauti and Maaden. Finally, we recover Kleene’s fixed-point theorem for omega-complete non-orders, again using attractivity to prove that Kleene’s fixed points are least quasi-fixed points.
Cite as

Akihisa Yamada and Jérémy Dubut. Complete Non-Orders and Fixed Points. In 10th International Conference on Interactive Theorem Proving (ITP 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 141, pp. 30:1-30:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)

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@InProceedings{yamada_et_al:LIPIcs.ITP.2019.30,
  author =	{Yamada, Akihisa and Dubut, J\'{e}r\'{e}my},
  title =	{{Complete Non-Orders and Fixed Points}},
  booktitle =	{10th International Conference on Interactive Theorem Proving (ITP 2019)},
  pages =	{30:1--30:16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-122-1},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{141},
  editor =	{Harrison, John and O'Leary, John and Tolmach, Andrew},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ITP.2019.30},
  URN =		{urn:nbn:de:0030-drops-110852},
  doi =		{10.4230/LIPIcs.ITP.2019.30},
  annote =	{Keywords: Order Theory, Lattice Theory, Fixed-Points, Isabelle/HOL}
}
Document
DOI: 10.4230/LIPIcs.CSL.2016.8
AC Dependency Pairs Revisited

Authors: Akihisa Yamada, Christian Sternagel, René Thiemann, and Keiichirou Kusakari

Published in: LIPIcs, Volume 62, 25th EACSL Annual Conference on Computer Science Logic (CSL 2016)

Abstract
Rewriting modulo AC, i.e., associativity and/or commutativity of certain symbols, is among the most frequently used extensions of term rewriting by equational theories. In this paper we present a generalization of the dependency pair framework for termination analysis to rewriting modulo AC. It subsumes existing variants of AC dependency pairs, admits standard dependency graph analyses, and in particular enjoys the minimality property in the standard sense. As a direct benefit, important termination techniques are easily extended; we describe usable rules and the subterm criterion for AC termination, which properly generalize the non-AC versions. We also perform these extensions within IsaFoR - the Isabelle formalization of rewriting - and thereby provide the first formalization of AC dependency pairs. Consequently, our certifier CeTA now supports checking proofs of AC termination.
Cite as

Akihisa Yamada, Christian Sternagel, René Thiemann, and Keiichirou Kusakari. AC Dependency Pairs Revisited. In 25th EACSL Annual Conference on Computer Science Logic (CSL 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 62, pp. 8:1-8:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2016)

Copy BibTex To Clipboard

@InProceedings{yamada_et_al:LIPIcs.CSL.2016.8,
  author =	{Yamada, Akihisa and Sternagel, Christian and Thiemann, Ren\'{e} and Kusakari, Keiichirou},
  title =	{{AC Dependency Pairs Revisited}},
  booktitle =	{25th EACSL Annual Conference on Computer Science Logic (CSL 2016)},
  pages =	{8:1--8:16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-022-4},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{62},
  editor =	{Talbot, Jean-Marc and Regnier, Laurent},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CSL.2016.8},
  URN =		{urn:nbn:de:0030-drops-65488},
  doi =		{10.4230/LIPIcs.CSL.2016.8},
  annote =	{Keywords: Equational Rewriting, Termination, Dependency Pairs, Certification}
}
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